Magnesium complexes of polyhydroxy compounds and their preparation

ABSTRACT

MAGNESIUM COMPLEXES OF POLYHYDROXY COMPPUNDS ARE PREPARED BY REACTING A MAGNESIUM ALKOXIDE WITH A POLYHYDROXY COMPOUND SUCH AS SORBITOL IN THE PRESENCE OF WATER. THE COMPLEXES PREFERABLY HAVE A RATIO OF ABOUT 0.1 TO ABOUT 0.7 GRAM ATOMS OF MAGNESIUM TO EACH HYDROXYL GROUP OF THE POLYHYDROXY COMPOUND.

United States Patent Office 3,803,250

Patented Apr. 9, 1974 kn Ho r, 't 's b lieved that the roduct is a mix-3,803,250 own Weve 1 1 e p MAGNESIUM COMPLEXES F POLYHYDROXY We cmpundstype:

COMPOUNDS AND THEIR PREPARATION Ludwig A. Hartmann, Wilmington, Del.,assignor to ICI America Inc., Wilmington, Del. 5 f f i No Drawing. FiledApr. 24, 1970, Ser. No. 31,751 H Mg- HC0 Int. (:1. C07c 31/30; A61k27/00 1 Mg R1 us. or. 260-635 K 12 Claims 11([3-0 ABSTRACT OF THEDISCLOSURE Magnesium complexes of polyhydroxy compounds are prepared byreacting a magnesium alkoxide with a polyhydroxy compound such assorbitol in the presence of pounds result from the reaction of apolyhydroxy comwater. The complexes preferably have a ratio of about 15pound 0.1 to about 0.7 gram atoms of magnesium to each hy- THE REACTIQNdroxyl group of the polyhydroxy compound.

where each R is appropriately selected from hydrogen, alkyl, or hydroxylsubstituted alkyl so that the above com- The reaction of the magnesiumalkoxide and the polyhydroxy compounds should be carried out in thepresence This invention relates to magnesium complexes of poly- 2 ofwater. This amount of water, in moles per gram atom hydroxy compoundsand to their preparation by reacting of magnesium, s q l to about 6 toabout 18 (Preferably a magnesium alkoxide with a polyhydroxy compound inabout 12) times the number" of gram atoms of magnesium the presence ofwater. These complexes are useful as ant- Charged divided y the numberof y y equivalents acids and may be used in the same manner as magnesiumof polyhydroxy compound charged. The use of excess hydroxide. They arealso useful as catalysts in organic water results in the formation ofmagnesium hydroxide reactions where a basic catalyst is used such as inisomaccompanied by a considerable amount of unreacted polyerizations,for example, the isomerization of glucose and hydroxy compound, whilethe use of insuflicient water refructose. sults in an incompletereaction of the magnesium alkoxide.

My related applications of the same filing date titled The m n of Water,in moles p gram i Method of Preparing Aluminum Complexes ofPolyhynesium, is preferably equal to about 6 to about 12 times droxyCompounds" and Magnesium-Aluminum C the number of gram atoms ofmagnesium charged divided plexes of Polyhydroxy Compounds and TheirPrepara by the number of hydroxyl equivalents of polyhydroxy tion, Ser.Nos. 31,749 and 31,750, respectively, and now p d charged when the ratioof am atoms of US. Pat. Nos. 3,686,249 and 3,631,083, respectively, maymagnesium to each y y group of the polyhydroxy be referred to foradditional information in this area. Compound is about to about 04 andis about 12 to abouti18 times the number of gram atoms of magnesiumSTARTING MATERIALS charged divided by the number of hydroxyl equivalentsof polyhydroxy compound charged when the above ratio xg gj gg gfig fsigggg kg ggg g gg 5 55; is about 0.4 to about 0.7; this is preferredbecause the hyhydric alcohol. The preferred magnesium alkoxides, which$2332; $2 2 5: d 2 gif olyhydroxy Compound tend to are easily obtamedhavethe form-11a -Mg(OR)2 Where R As the reaction proceeds and thereaction mixture "l P to C4;.magnes1qm ethoxlde 1s prelerred becaiusethickens enough water-miscible solvent may be added to g gsg g iggg 2:Mlxture's of magneslum alkoxldes dilute the mixture so that it may beeasily stirred. Dioxane,

methyl Cellosolve (ethylene glycol monomethyl ether), g: E2 g s x i zfggi 9fi s gi alcohols such as methanol, ethanol, propanol, orisoprohydroiy compounds z g g g i g ggz i g; panol, etc., are examplesof suitable solvents; alcohols from 3 to 6 carbon atoms and are linearor branched, are preferredras they are inexpesive, easily distilled, and

the polyhydroxy compounds are very soluble in them. preferably.hnear andRre.ferab1y.have 2 to hydloxyl The temperature of the reaction is notcritical, but about groups which may be vicmal or in a 1,3-relat1onsh1pto C is preferred each other. Suitable polyhydroxy compounds includepro- After the alkoxide and the Polyhydroxy compound have Pylene glycoland 23'b1ty1ene glycols, reacted to form the complex, the complex isdried. This 3- and zi4'pentylene glycols, 1,3, is preferably done byvacuum treating under slightly re- 2,4-hexy1ene glycols, glycerol,butanetriols, pentanetriols,

duced pressure at about 55 to about 90 C. hexanetriols, erythritol,pentanetetrols, hexanetetrols, xylihil h d i t e e th e ce alcohol, it

boxauopoutols, Sorbitol, maunitol, and duloitol; does not remove thealcohol which is attached to the bitol is preferred as it is readilyavailable. Also contemcomplex in the form of unreacted alkoxide. Thisalcohol plated are mixtures of polyhydroxy compounds and polyis strippedfrom the complex by vacuum distilling under mers of polyhydroxycompounds such as hydroxyl bear- 0 less than 1 millimeter of mercurywith thorough agitation ing polyethers, e.g., diglycerol, polyglycerols,etc, and heating, preferably to about 55 C. to about 90 C.

(below 55 C. too much time is required to make the THE COMPLEX processpractical and above 90 C. the complex tends The complexes preferablyhave a ratio of about 0.1 to to decompose) about 0.7 gram atoms ofmagnesium to each hydroxyl E The f g l f futher llhllsfrate thlsmventlon group of the polyhydroxy compound. Ratios outside of xamp e emgepre erre examp this range may result in large amounts of unreacted in-ExamP1e I gredients, polymeric structures, or the dilution of the Atwo-liter flask equipped with a thermometer, reflux magnesium to a levelwhere the complex becomes less condenser, and an air-driven stirrer wascharged with effective. 14.6 g. of magnesium turnings, 950 ml. absoluteethanol, The exact structure of the complex produced is not and 2 ml.carbon tetrachloride. The mixture was stirred and warmed on the steambath and allowed to react at 78 C. for 24 hours. After 19' hours 20 ml.of xylene was added to help complete the reaction. When all themagnesium had reacted toform magnesium ethoxide, a solution of 54.6 g.of sorbitol and 32.6 ml. of water was added at 65 C.'and the thin slurrywas mixed well for ten minutes. Drying was then carried out at 60 C. and200 mm. for 30 minutes at 60 C. and 20-40 mm. for 1% hours and thegranular product was then held at 60 to 70 C. and 0.4 mm. for 16 hours.The product was ground and passed through a 60 mesh screen before finalstripping at 70 C. and 0.3 mm. for one day and 115 to 120 C. at 0.3 mm.for 16 hours. The final yield was 73.8 g. Analysis showed carbon, 28.3%;hydrogen, 5.13%; ash, 30.67%; ethanol, 0.009%; 99.9% alkoxide reacted;and free sorbitol, 2.7%. The approximate molar ratio of sorbitol tomagnsium to inorganic hydroxyl groups was 1:2:1 in the complex (thosehydroxyl groups attached tov the magnesium and titratable with acid arereferred to herein as inorganic").

Example 11 Using the same procedure that was used in Example I, a flaskwas charged with 14.6 g. magnesium turnings and 750 ml. methyl alcoholcontaining 1 ml. CCI The reaction proceeded at 65 C. for 40 minutes toproduce magnesium methoxide; additional methanol (750 ml.) was addedduring the reaction as a diluent. Then 109.3 g. of sorbitol was addedfollowed by 17 ml. of water in 50 ml. methanol. The reaction wasallowed. to proceed at 65 C. for one hour. Vacuum drying and strippingwas carried out at 50 to 70 C. and 200 mm. down to 50 mm. for 6% hours,70 to 80 C. and 20 down to 3 mm. for 6 hours and 115 to 120 C. at lessthan 1 mm. for 24 hours. 121.2 g. of product were obtained. Analysisshowed 12.05% magnesium, 34.97% carbon, 5.75% hydrogen, 20.4% ash, and0.5% alcohol. The molar ratio of sorbitol to magnesium in the productwas 1 to 1.

Example III Using the same procedure that was used in Example I, a flaskwas charged with 14.6 g. magnesium, 150 ml. ethanol, 30 ml. xylene, and1 ml. CCh. The reaction proceeded at 80 C. for 6 hours to producemagnesium ethoxide. Additional ethanol (750 ml.) was added followed by36.4 g. sorbitol in 53.6 ml. water; the reaction proceeded at 70 C. for1% hours. The product was then vacuum dried and stripped at 50 to 7 C.and 200 down to 50 mm. for 8 hours, 70 to 80 C. and 20 down to 3 mm. for26 hours and 115 to 120 C. at less than 1 mm. for 7 hours. Analysisshowed 22.9% magnesium, 24.57% carbon, 4. 89% hydrogen, 30.3% ash, 0.09%alcohol, and 0.2% free sorbitol. The approximate molar ratio ofsorbr'tol to magnesium to inorganic hydroxyl groups was 1:321.

Example IV A flask equipped with thermometer, reflux condenser,

and stirrer is charged with 14.6 g. magnesium turnings, 950 ml. absoluteisopropyl alcohol, 20 m1. xylene and 2 ml. C01 The mixture is treated onthe steam bathunder reflux until magnesium isopropoxide is produced.Aqueous erythritol (73 g. erythritol and 32 g. water) is then added atabout 65 C. and the resultant slurry mixed well at that temperature.Vacuum drying is carried out initially at -70 C. with the aid of aslight vacuum for several hours. Stripping is carried out at 100-110" C.and high vacuum for several hours. The product is a light-colored solidand has a molar ratio of erythritol to magnesium of 1 to 1.

Example V A flask equipped with thermometer, reflux condenser, andstirrer is charged with 14.6 g. magnesium turmngs,

95.0 ml. absolute ethanol, 20 ml. xylene, and 2 ml. CCl The mixture istreated on the steam bath under reflux until magnesium ethoxide isproduced. Aqueous propylene glycol (45.6 propylene glycol and 75 g.water) is then added at about 65 C. and the resultant slurry mixed wellat that temperature. Vacuum drying is carried out initially at 6070 C.with the aid of slight vacuum for several hours. Stripping is carriedout at -110 C. and high vacuum for several hours. The product has amolar ratio of propylene glycol to magnesium of 1 to 1.

What is claimed is:

1. A magnesium derivative of a polyhydroxy compound having a ratio ofabout 0.1 to about 0.7 gram atoms of magnesium to each hydroxyl group ofpolyhydroxy compound consisting-essentially of the product formed by (a)reacting magnesium alkoxide with a polyhydroxy compound selected fromthe group consisting of erythritol, hexanetetrols, hexanepentols,xylitol, sorbitol, mannitol, and dulcitol in the presence of an amountof water, in moles per gram atom of magnesium, equal to about 6 to about18 times the number of gram atoms of magnesium charged divided by thenumber of hydroxyl equivalents of polyhydroxy compound charged; (b)drying the product formed in step (a); and then (c) vacuum strippingwith heating the product of step (b) at a final vacuum of less than onemillimeter of mercury with thorough agitation.

2.: A derivative according to claim 1 wherein the magnesium alkoxidereactant has the formula Mg(OR) where R is alkyl to C 3. The magnesiumderivative of claim 1 wherein the amount of water, in moles per gramatom of magnesium, is equal to about 12 times the number of gram atomsof magnesium charged divided by the number of hydroxyl equivalents ofpolyhydroxy compound charged.

4. The magnesium drivative of claim 1 wherein the amount of water, inmoles per gram atom of magnesium, is equal to about 6 to about 12 timesthe number of gram atoms of magnesium charged divided by the number ofhydroxyl equivalents of polyhydroxy compound charged when the ratio ofgram atoms of magnesium to each hydroxyl group of polyhydroxy compoundis about 0.1 to about 0.4 and the amount of water, in moles per gramatom of magnesium, is equal to about 12 to about 18 times the number ofgram atoms of magnesium charged divided by the number of hydroxylequivalents ofpolyhydroxy compound charged when the ratio of gram atomsof magnesium to each hydroxyl group of polyhydroxy compound is about 0.4to about 0.7.

5. The magnesium derivative of claim 1 wherein said polyhydroxy compoundis sorbitol.

6. The magnesium derivative of claim 1 wherein said magnesium alkoxideis magnesium ethoxide.

7. A process of producing a magnesium derivative of a polyhydroxycompound having a ratio of about 0.1 to about 0.7 gram atoms ofmagnesium to each hydroxyl group of polyhydroxy compound consistingessentially of reacting (a) a magnesium alkoxide having the formulaMg(OR) with a polyhydroxy compound selected from the group consisting ofalkane polyols having from 3 to 6 carbon atoms and 2 m6 hydroxyl groupsand diglycerol, said reaction taking place in the presence of an amountof water, in moles per gram atom of magnesium, equal to about 6 to about18 times the number of gram atoms of magnesium charged divided by thenumber of hydroxyl equivalents of polyhydroxy compound charged, where Ris alkyl to C (1)) drying the product formed in step (a); and then (0)vacuum stripping with heating the product of step (b) at a final vacuumof less than one millimeter of mercury wth thorough agitation.

8. The process of claim 7 wherein the amount of water is, in molesper'gram atom of magnesium, equal to about 12 times the number 'of gramatoms of magnesium charged divided by the number of hydroxyl equivalentsof polyhydroxy compound charged.

9. The process of elaim'7 wherein said polyhydroxy compound is sorbitol.

10. The process of claim 7 wherein said magnesium alkoxide is magnesiumethoxide.

11. The process of claim 7 wherein the vacuum stripping is carried outat about 55 to about 90 C.

12. The process of claim 7 wherein a water-miscible solvent selectedfrom the group consisting of dioxane, ethylene glycol monomethyl ether,methanol, ethanol, propanol and isopropanol is present during thereaction.

References Cited UNITED STATES PATENTS 2,755,220 7/1956 Alford et al.23-201 2,510,550 6/1950 'Byrns 260-632 A 1,712,830 5/ 1929 Kyrides260632 A OTHER REFERENCES Turova et al., Russian Chemical Reviews, vol.34

19 (1965), pp. 161-185, pp; 161-165 and 169 supplied.

